Fixed bug #27362: crash at evaluation of IN predicate when one
of its argument happened to be a decimal expression returning
the NULL value.
The crash was due to the fact the function in_decimal::set did
not take into account that val_decimal() could return 0 if
the decimal expression had been evaluated to NULL.
mysql-test/r/func_in.result:
Added a test case for bug #27362.
mysql-test/t/func_in.test:
Added a test case for bug #27362.
sql/item_cmpfunc.cc:
Fixed bug #27362: crash at evaluation of IN predicate when one
of its argument happened to be a decimal expression returning
the NULL value.
The crash was due to the fact the function in_decimal::set did
not take into account that val_decimal() could return 0 if
the decimal expression had been evaluated to NULL.
into zippy.cornsilk.net:/home/cmiller/work/mysql/mysql-5.0-community
VC++Files/sql/mysqld.vcproj:
Auto merged
include/config-win.h:
Auto merged
myisam/mi_open.c:
Auto merged
mysql-test/r/information_schema_db.result:
Auto merged
ndb/src/common/util/File.cpp:
Auto merged
sql/Makefile.am:
Auto merged
sql/ha_archive.cc:
Auto merged
sql/ha_berkeley.cc:
Auto merged
sql/ha_myisam.cc:
Auto merged
sql/ha_myisammrg.cc:
Auto merged
sql/ha_ndbcluster.cc:
Auto merged
sql/item_cmpfunc.cc:
Auto merged
sql/item_func.cc:
Auto merged
sql/lock.cc:
Auto merged
sql/log_event.cc:
Auto merged
sql/repl_failsafe.cc:
Auto merged
sql/set_var.cc:
Auto merged
sql/set_var.h:
Auto merged
sql/sp_head.cc:
Auto merged
sql/sql_base.cc:
Auto merged
sql/sql_cache.cc:
Auto merged
sql/sql_class.cc:
Auto merged
sql/sql_class.h:
Auto merged
sql/sql_delete.cc:
Auto merged
sql/sql_insert.cc:
Auto merged
sql/sql_lex.cc:
Auto merged
sql/sql_lex.h:
Auto merged
sql/sql_prepare.cc:
Auto merged
sql/sql_repl.cc:
Auto merged
sql/sql_select.cc:
Auto merged
sql/sql_show.cc:
Auto merged
sql/sql_table.cc:
Auto merged
sql/sql_update.cc:
Auto merged
sql/sql_view.cc:
Auto merged
sql/sql_yacc.yy:
Auto merged
sql/table.h:
Auto merged
support-files/mysql.spec.sh:
Auto merged
configure.in:
Manual merge.
include/my_dbug.h:
Manual merge.
sql/mysql_priv.h:
Manual merge.
sql/mysqld.cc:
Manual merge.
sql/slave.cc:
Manual merge.
sql/sql_parse.cc:
Manual merge.
- Problem: data separators were copied to a fixed-size buffer
on the stack; memcpy was used, without bounds checking; a
server crash could result if long FIELDS ENCLOSED BY, etc.,
was given
- Fix: write the separators directly, instead of copying to
a buffer first (in select_export::send_data())
sql/sql_class.cc:
In select_export::send_data(), write data separators
directly, instead of copying into a fixed-size memory
buffer before writing. This avoids a buffer overflow
when very large separators are specified.
sql/item_cmpfunc.cc:
Ensure both operands of a comparison are cast to "ulonglong", not just one only.
Without this, some 64-bit big-endian hosts failed test "func_in" when 5.0.38 builds were started.
Patch provided by Timothy.
- Build sql files for netware from the mysql_system_tables*.sq files
- Fix comments about mysql_create_system_tables.sh
- Use mysql_install_db.sh to create system tables for mysql_test-run-shell
- Fix mysql-test-run.pl to also look in share/mysql for the msyql_system*.sql files
Changeset coded today by Magnus Svensson, just the application to 5.0.38 is by Joerg Bruehe.
BitKeeper/deleted/.del-init_db.sql~e2b8d0c8390e8023:
Delete: netware/init_db.sql
BitKeeper/deleted/.del-test_db.sql:
Delete: netware/test_db.sql
BitKeeper/etc/ignore:
Added netware/init_db.sql netware/test_db.sql to the ignore list
mysql-test/install_test_db.sh:
Use mysql_install_db from install_test_db(which is used by mysql-test-run-shell)
to install the system tables
mysql-test/mysql-test-run.pl:
Look for the mysql_system_tables*.sql also in share/mysql
netware/Makefile.am:
Build netware/init_db.sql and netware/test_db.sql from
the sources in scripts/msyql_system_tables*.sql
scripts/make_binary_distribution.sh:
netware/init_db.sql and netware/test_db.sql are now built by the Makefiles
from the scripts/mysql_system_tables*.sql files
sql/mysql_priv.h:
Update comment remindging to update the MySQL system table definitions
when adding a new SQL_MODE
sql/sql_acl.h:
Update comment reminding to update the MySQL System tables
when changing the ACL defines
TABLE ... WRITE".
Memory and CPU hogging occured when connection which had to wait for table
lock was serviced by thread which previously serviced connection that was
killed (note that connections can reuse threads if thread cache is enabled).
One possible scenario which exposed this problem was when thread which
provided binlog dump to replication slave was implicitly/automatically
killed when the same slave reconnected and started pulling data through
different thread/connection.
The problem also occured when one killed particular query in connection
(using KILL QUERY) and later this connection had to wait for some table
lock.
This problem was caused by the fact that thread-specific mysys_var::abort
variable, which indicates that waiting operations on mysys layer should
be aborted (this includes waiting for table locks), was set by kill
operation but was never reset back. So this value was "inherited" by the
following statements or even other connections (which reused the same
physical thread). Such discrepancy between this variable and THD::killed
flag broke logic on SQL-layer and caused CPU and memory hogging.
This patch tries to fix this problem by properly resetting this member.
There is no test-case associated with this patch since it is hard to test
for memory/CPU hogging conditions in our test-suite.
sql/mysqld.cc:
We should not forget to reset THD::mysys_var::abort after kill operation
if we are going to use thread to which this operation was applied for
handling of other connections.
sql/sp_head.cc:
We should not forget to reset THD::mysys_var::abort after kill operation
if we are going to use thread to which this operation was applied for
handling of further statements.
sql/sql_parse.cc:
We should not forget to reset THD::mysys_var::abort after kill operation
if we are going to use thread to which this operation was applied for
handling of further statements.
TABLE ... WRITE".
CPU hogging occured when connection which had to wait for table lock was
serviced by thread which previously serviced connection that was killed
(note that connections can reuse threads if thread cache is enabled).
One possible scenario which exposed this problem was when thread which
provided binlog dump to replication slave was implicitly/automatically
killed when the same slave reconnected and started pulling data through
different thread/connection.
In 5.* versions memory hogging was added to CPU hogging. Moreover in
those versions the problem also occured when one killed particular query
in connection (using KILL QUERY) and later this connection had to wait for
some table lock.
This problem was caused by the fact that thread-specific mysys_var::abort
variable, which indicates that waiting operations on mysys layer should
be aborted (this includes waiting for table locks), was set by kill
operation but was never reset back. So this value was "inherited" by the
following statements or even other connections (which reused the same
physical thread). Such discrepancy between this variable and THD::killed
flag broke logic on SQL-layer and caused CPU and memory hogging.
This patch tries to fix this problem by properly resetting this member.
There is no test-case associated with this patch since it is hard to test
for memory/CPU hogging conditions in our test-suite.
sql/mysqld.cc:
We should not forget to reset THD::mysys_var::abort after kill operation
if we are going to use thread to which this operation was applied for
handling of other connections.
into mysql.com:/home/svoj/devel/mysql/BUG26881/mysql-5.0-engines
myisam/mi_create.c:
Auto merged
mysql-test/t/merge.test:
Auto merged
sql/ha_myisam.cc:
Auto merged
sql/sql_parse.cc:
Use local.
mysql-test/r/merge.result:
SCCS merged
differences in tables
Certain merge tables were wrongly reported as having incorrect definition:
- Some fields that are 1 byte long (e.g. TINYINT, CHAR(1)), might
be internally casted (in certain cases) to a different type on a
storage engine layer. (affects 4.1 and up)
- If tables in a merge (and a MERGE table itself) had short VARCHAR column (less
than 4 bytes) and at least one (but not all) tables were ALTER'ed (even to an
identical table: ALTER TABLE xxx ENGINE=yyy), table definitions went ouf of
sync. (affects 4.1 only)
This is fixed by relaxing a check for underlying conformance and setting
field type to FIELD_TYPE_STRING in case varchar is shorter than 4
when a table is created.
myisam/mi_create.c:
Added a comment.
mysql-test/r/merge.result:
A test case for bug#26881.
mysql-test/t/merge.test:
A test case for bug#26881.
sql/ha_myisam.cc:
Relaxed some checks performed by check_definition():
As comparing of fulltext keys (and key segments) is not yet implemented,
only return an error in case one of keys is fulltext and other is not.
Otherwise, if both keys are fulltext, accept them as is.
As comparing of spatial keys (and key segments) is not yet implemented,
only return an error in case one of keys is spatial and other is not.
Otherwise, if both keys are spatial, accept them as is.
A workaround to handle situation when field is casted from FIELD_SKIP_ZERO
to FIELD_NORMAL. This could happen only in case field length is 1 and row
format is fixed.
sql/sql_parse.cc:
When a table that has varchar field shorter than 4 is created, field type is
set to FIELD_TYPE_VAR_STRING. Later, when a table is modified using alter
table, field type is changed to FIELD_TYPE_STRING (see Field_string::type).
That means HA_OPTION_PACK_RECORD flag might be lost and thus null_bit might
be shifted by alter table, in other words alter table doesn't create 100%
equal table definition.
This is usually not a problem, since when a table is created/altered,
definition on a storage engine layer is based on one that is passed from
sql layer. But it is a problem for merge engine - null_bit is shifted when
a table (merge or underlying) is altered.
Set field type to FIELD_TYPE_STRING in case FIELD_TYPE_VAR_STRING is shorter
than 4 when a table is created as it is done in Field::type.
When the SUBSTRING() function was used over a LONGTEXT field the max_length of
the SUBSTRING() result was wrongly calculated and set to 0. As the max_length
parameter is used while tmp field creation it limits the length of the result
field and leads to printing an empty string instead of the correct result.
Now the Item_func_substr::fix_length_and_dec() function correctly calculates
the max_length parameter.
mysql-test/t/func_str.test:
Added a test case for the bug#15757: Wrong SUBSTRING() result when a tmp table was employed.
mysql-test/r/func_str.result:
Added a test case for the bug#15757: Wrong SUBSTRING() result when a tmp table was employed.
sql/item_strfunc.cc:
Bug#15757: Wrong SUBSTRING() result when a tmp table was employed.
Now the Item_func_substr::fix_length_and_dec() function correctly calculates
the max_length parameter.
into moonbone.local:/mnt/gentoo64/work/25373-bug-5.0-opt-mysql
mysql-test/r/func_str.result:
Auto merged
mysql-test/r/subselect.result:
Auto merged
mysql-test/r/union.result:
Auto merged
sql/item.cc:
Auto merged
Crash happened because the function get_best_group_min_max detected
joins with ROLLUP incorrectly.
mysql-test/r/olap.result:
Added a test case for bug #26830.
mysql-test/t/olap.test:
Added a test case for bug #26830.
away.
Additional fix for bug#22331. Now Item_field prints its value in the case of
the const field.
mysql-test/r/varbinary.result:
Corrected test case after fix for bug#22331.
mysql-test/r/union.result:
Corrected test case after fix for bug#22331.
mysql-test/r/subselect.result:
Corrected test case after fix for bug#22331.
mysql-test/r/func_test.result:
Corrected test case after fix for bug#22331.
mysql-test/r/having.result:
Corrected test case after fix for bug#22331.
mysql-test/r/func_regexp.result:
Corrected test case after fix for bug#22331.
mysql-test/r/func_str.result:
Corrected test case after fix for bug#22331.
mysql-test/r/func_default.result:
Corrected test case after fix for bug#22331.
mysql-test/r/explain.result:
Corrected test case after fix for bug#22331.
sql/sql_union.cc:
Bug#22331: Wrong WHERE in EXPLAIN EXTENDED when all expressions were optimized
away.
Cleanup of the SELECT_LEX::order_list list.
sql/item.h:
Bug#22331: Wrong WHERE in EXPLAIN EXTENDED when all expressions were optimized
away.
Added the print() member function to the Item_field class.
sql/item.cc:
Bug#22331: Wrong WHERE in EXPLAIN EXTENDED when all expressions were optimized
away.
Added the print() member function to the Item_field class.
into magare.gmz:/home/kgeorge/mysql/autopush/B26281-5.0-opt
sql/item_strfunc.cc:
Auto merged
mysql-test/r/func_str.result:
resolved test merge conflicts
mysql-test/t/func_str.test:
resolved test merge conflicts
Fixed boundry checks in the INSERT() function:
were one off.
mysql-test/r/func_str.result:
Bug #26281: test case
mysql-test/t/func_str.test:
Bug #26281: test case
sql/item_strfunc.cc:
Bug #26281: fixed boundry checks
construct references invalid name.
Derived tables currently cannot use outer references.
Thus there is no outer context for them.
The 4.1 code takes this fact into account while the
Item_field::fix_outer_field code of 5.0 lost the check that blocks
any attempts to resolve names in outer context for derived tables.
mysql-test/r/union.result:
Added a test case for bug #26661.
mysql-test/t/union.test:
Added a test case for bug #26661.
sql/item.cc:
Fixed bug #26661.
Derived tables currently cannot use outer references.
Thus there is no outer context for them.
The 4.1 code takes this fact into account while the
Item_field::fix_outer_field code of 5.0 lost the check that blocks
any attempts to resolve names in outer context for derived tables.
into mysql.com:/home/hf/work/mrg/mysql-5.0-opt
mysql-test/r/order_by.result:
Auto merged
mysql-test/r/subselect.result:
Auto merged
mysql-test/t/order_by.test:
Auto merged
mysql-test/t/sp.test:
Auto merged
sql/item.cc:
Auto merged
sql/item_cmpfunc.cc:
Auto merged
sql/item_cmpfunc.h:
Auto merged
sql/item_func.cc:
Auto merged
sql/mysql_priv.h:
Auto merged
sql/sql_base.cc:
Auto merged
sql/sql_insert.cc:
Auto merged
sql/sql_lex.cc:
Auto merged
sql/sql_lex.h:
Auto merged
sql/sql_load.cc:
Auto merged
sql/sql_parse.cc:
Auto merged
sql/sql_select.cc:
Auto merged
sql/sql_update.cc:
Auto merged
mysql-test/r/func_str.result:
merging
mysql-test/r/sp.result:
merging
mysql-test/r/view.result:
merging
mysql-test/t/func_str.test:
merging
mysql-test/t/view.test:
merging
into quadxeon.mysql.com:/benchmarks/ext3/TOSAVE/tsmith/bk/maint/mrg0306/50
sql/mysqld.cc:
Auto merged
sql/sql_class.cc:
Auto merged
sql/sql_class.h:
Auto merged
sql/sql_parse.cc:
Auto merged
Postfix for bug#22331 for windows platform.
explain.test, explain.result:
Cleanup after bugfix#22331.
mysql-test/t/explain.test:
Cleanup after bugfix#22331.
mysql-test/r/explain.result:
Cleanup after bugfix#22331.
sql/sql_select.cc:
Postfix for bug#22331 for windows platform.
into moonbone.local:/mnt/gentoo64/work/25373-bug-5.0-opt-mysql
mysql-test/r/subselect.result:
Auto merged
sql/sql_lex.h:
Auto merged
sql/sql_select.cc:
Auto merged
sql/sql_lex.cc:
SCCS merged
result.
For built-in functions like sqrt() function names are hard-coded and can be
compared by pointer. But this isn't the case for a used-defined stored
functions - names there are dynamical and should be compared as strings.
Now the Item_func::eq() function employs my_strcasecmp() function to compare
used-defined stored functions names.
mysql-test/t/sp.test:
Added a test case for bug#25373: Stored functions wasn't compared correctly which leads to a wrong result.
mysql-test/r/sp.result:
Added a test case for bug#25373: Stored functions wasn't compared correctly which leads to a wrong result.
sql/item_func.cc:
Bug#25373: Stored functions wasn't compared correctly which leads to a wrong
result.
Now the Item_func::eq() function employs my_strcasecmp() function to compare
used-defined stored functions names.
away.
During optimization stage the WHERE conditions can be changed or even
be removed at all if they know for sure to be true of false. Thus they aren't
showed in the EXPLAIN EXTENDED which prints conditions after optimization.
Now if all elements of an Item_cond were removed this Item_cond is substituted
for an Item_int with the int value of the Item_cond.
If there were conditions that were totally optimized away then values of the
saved cond_value and having_value will be printed instead.
mysql-test/t/explain.test:
Added a test case for the bug#22331: Wrong WHERE in EXPLAIN EXTENDED when all expressions were optimized away.
mysql-test/r/subselect.result:
Corrected test case result after fix for bug#22331.
mysql-test/r/func_test.result:
Corrected test case result after fix for bug#22331.
mysql-test/r/explain.result:
Added a test case for the bug#22331: Wrong WHERE in EXPLAIN EXTENDED when all expressions were optimized away.
sql/sql_select.cc:
Bug#22331: Wrong WHERE in EXPLAIN EXTENDED when all expressions were optimized
away.
Now if all elements of an Item_cond were removed this Item_cond is substituted
for an Item_int with the int value of the Item_cond.
If there were conditions that were totally optimized away then values of the
saved cond_value and having_value will be printed instead.
sql/sql_lex.h:
Bug#22331: Wrong WHERE in EXPLAIN EXTENDED when all expressions were optimized
away.
The cond_value and the having_value variables are
added to the SELECT_LEX class.
sql/sql_lex.cc:
Bug#22331: Wrong WHERE in EXPLAIN EXTENDED when all expressions were optimized
away.
The initialization of the cond_value and the having_value variables.
sql/sql_select.h:
Bug#22331: Wrong WHERE in EXPLAIN EXTENDED when all expressions were optimized
away.
Now having_value is also stored in the JOIN class.
into bodhi.local:/opt/local/work/mysql-5.0-26750
sql/mysqld.cc:
Auto merged
sql/sql_class.cc:
Auto merged
sql/sql_parse.cc:
Auto merged
sql/sql_class.h:
Manual merge.
fixes).
The legend: on a replication slave, in case a trigger creation
was filtered out because of application of replicate-do-table/
replicate-ignore-table rule, the parsed definition of a trigger was not
cleaned up properly. LEX::sphead member was left around and leaked
memory. Until the actual implementation of support of
replicate-ignore-table rules for triggers by the patch for Bug 24478 it
was never the case that "case SQLCOM_CREATE_TRIGGER"
was not executed once a trigger was parsed,
so the deletion of lex->sphead there worked and the memory did not leak.
The fix:
The real cause of the bug is that there is no 1 or 2 places where
we can clean up the main LEX after parse. And the reason we
can not have just one or two places where we clean up the LEX is
asymmetric behaviour of MYSQLparse in case of success or error.
One of the root causes of this behaviour is the code in Item::Item()
constructor. There, a newly created item adds itself to THD::free_list
- a single-linked list of Items used in a statement. Yuck. This code
is unaware that we may have more than one statement active at a time,
and always assumes that the free_list of the current statement is
located in THD::free_list. One day we need to be able to explicitly
allocate an item in a given Query_arena.
Thus, when parsing a definition of a stored procedure, like
CREATE PROCEDURE p1() BEGIN SELECT a FROM t1; SELECT b FROM t1; END;
we actually need to reset THD::mem_root, THD::free_list and THD::lex
to parse the nested procedure statement (SELECT *).
The actual reset and restore is implemented in semantic actions
attached to sp_proc_stmt grammar rule.
The problem is that in case of a parsing error inside a nested statement
Bison generated parser would abort immediately, without executing the
restore part of the semantic action. This would leave THD in an
in-the-middle-of-parsing state.
This is why we couldn't have had a single place where we clean up the LEX
after MYSQLparse - in case of an error we needed to do a clean up
immediately, in case of success a clean up could have been delayed.
This left the door open for a memory leak.
One of the following possibilities were considered when working on a fix:
- patch the replication logic to do the clean up. Rejected
as breaks module borders, replication code should not need to know the
gory details of clean up procedure after CREATE TRIGGER.
- wrap MYSQLparse with a function that would do a clean up.
Rejected as ideally we should fix the problem when it happens, not
adjust for it outside of the problematic code.
- make sure MYSQLparse cleans up after itself by invoking the clean up
functionality in the appropriate places before return. Implemented in
this patch.
- use %destructor rule for sp_proc_stmt to restore THD - cleaner
than the prevoius approach, but rejected
because needs a careful analysis of the side effects, and this patch is
for 5.0, and long term we need to use the next alternative anyway
- make sure that sp_proc_stmt doesn't juggle with THD - this is a
large work that will affect many modules.
Cleanup: move main_lex and main_mem_root from Statement to its
only two descendants Prepared_statement and THD. This ensures that
when a Statement instance was created for purposes of statement backup,
we do not involve LEX constructor/destructor, which is fairly expensive.
In order to track that the transformation produces equivalent
functionality please check the respective constructors and destructors
of Statement, Prepared_statement and THD - these members were
used only there.
This cleanup is unrelated to the patch.
sql/log_event.cc:
THD::main_lex is private and should not be used.
sql/mysqld.cc:
Move MYSQLerror to sql_yacc.yy as it depends on LEX headers now.
sql/sql_class.cc:
Cleanup: move main_lex and main_mem_root to THD and Prepared_statement
sql/sql_class.h:
Cleanup: move main_lex and main_mem_root to THD and Prepared_statement
sql/sql_lex.cc:
Implement st_lex::restore_lex()
sql/sql_lex.h:
Declare st_lex::restore_lex().
sql/sql_parse.cc:
Consolidate the calls to unit.cleanup() and deletion of lex->sphead
in mysql_parse (COM_QUERY handler)
sql/sql_prepare.cc:
No need to delete lex->sphead to restore memory roots now in case of a
parse error - this is done automatically inside MYSQLparse
sql/sql_trigger.cc:
This code could lead to double deletion apparently, as in case
of an error lex.sphead was never reset.
sql/sql_yacc.yy:
Trap all returns from the parser to ensure that MySQL-specific cleanup
is invoked: we need to restore the global state of THD and LEX in
case of a parsing error. In case of a parsing success this happens as
part of normal grammar reduction process.
into quadxeon.mysql.com:/benchmarks/ext3/TOSAVE/tsmith/bk/maint/mrg0306/50
mysql-test/mysql-test-run.pl:
Auto merged
mysql-test/r/sp.result:
Auto merged
mysql-test/t/sp.test:
Auto merged
sql/item_cmpfunc.cc:
Auto merged
sql/item_cmpfunc.h:
Auto merged
sql/mysqld.cc:
Auto merged
sql/sql_class.cc:
Auto merged
sql/sql_class.h:
Auto merged
sql/sql_parse.cc:
Auto merged
Functions over sum functions wasn't set up correctly for the ORDER BY clause
which leads to a wrong order of the result set.
The split_sum_func() function is called now for each ORDER BY item that
contains a sum function to set it up correctly.
mysql-test/t/order_by.test:
Added a test case for bug#25376: Incomplete setup of ORDER BY clause results in a wrong result.
mysql-test/r/order_by.result:
Added a test case for bug#25376: Incomplete setup of ORDER BY clause results in a wrong result.
sql/sql_select.cc:
Bug#25376: Incomplete setup of ORDER BY clause results in a wrong result.
The split_sum_func() function is called now for each ORDER BY item that
contains a sum function to set it up correctly.
into weblab.(none):/home/marcsql/TREE/mysql-5.0-8407_b
mysql-test/r/view.result:
Auto merged
sql/mysqld.cc:
Auto merged
sql/sp_head.cc:
Auto merged
sql/sp_head.h:
Auto merged
sql/sql_class.cc:
Auto merged
sql/sql_class.h:
Auto merged
sql/sql_update.cc:
Auto merged
sql/table.cc:
Auto merged
sql/table.h:
Auto merged
sql/sql_base.cc:
Manual merge
Bug 18914 (Calling certain SPs from triggers fail)
Bug 20713 (Functions will not not continue for SQLSTATE VALUE '42S02')
Bug 21825 (Incorrect message error deleting records in a table with a
trigger for inserting)
Bug 22580 (DROP TABLE in nested stored procedure causes strange dependency
error)
Bug 25345 (Cursors from Functions)
This fix resolves a long standing issue originally reported with bug 8407,
which affect the behavior of Stored Procedures, Stored Functions and Trigger
in many different ways, causing symptoms reported by all the bugs listed.
In all cases, the root cause of the problem traces back to 8407 and how the
server locks tables involved with sub statements.
Prior to this fix, the implementation of stored routines would:
- compute the transitive closure of all the tables referenced by a top level
statement
- open and lock all the tables involved
- execute the top level statement
"transitive closure of tables" means collecting:
- all the tables,
- all the stored functions,
- all the views,
- all the table triggers
- all the stored procedures
involved, and recursively inspect these objects definition to find more
references to more objects, until the list of every object referenced does
not grow any more.
This mechanism is known as "pre-locking" tables before execution.
The motivation for locking all the tables (possibly) used at once is to
prevent dead locks.
One problem with this approach is that, if the execution path the code
really takes during runtime does not use a given table, and if the table is
missing, the server would not execute the statement.
This in particular has a major impact on triggers, since a missing table
referenced by an update/delete trigger would prevent an insert trigger to run.
Another problem is that stored routines might define SQL exception handlers
to deal with missing tables, but the server implementation would never give
user code a chance to execute this logic, since the routine is never
executed when a missing table cause the pre-locking code to fail.
With this fix, the internal implementation of the pre-locking code has been
relaxed of some constraints, so that failure to open a table does not
necessarily prevent execution of a stored routine.
In particular, the pre-locking mechanism is now behaving as follows:
1) the first step, to compute the transitive closure of all the tables
possibly referenced by a statement, is unchanged.
2) the next step, which is to open all the tables involved, only attempts
to open the tables added by the pre-locking code, but silently fails without
reporting any error or invoking any exception handler is the table is not
present. This is achieved by trapping internal errors with
Prelock_error_handler
3) the locking step only locks tables that were successfully opened.
4) when executing sub statements, the list of tables used by each statements
is evaluated as before. The tables needed by the sub statement are expected
to be already opened and locked. Statement referencing tables that were not
opened in step 2) will fail to find the table in the open list, and only at
this point will execution of the user code fail.
5) when a runtime exception is raised at 4), the instruction continuation
destination (the next instruction to execute in case of SQL continue
handlers) is evaluated.
This is achieved with sp_instr::exec_open_and_lock_tables()
6) if a user exception handler is present in the stored routine, that
handler is invoked as usual, so that ER_NO_SUCH_TABLE exceptions can be
trapped by stored routines. If no handler exists, then the runtime execution
will fail as expected.
With all these changes, a side effect is that view security is impacted, in
two different ways.
First, a view defined as "select stored_function()", where the stored
function references a table that may not exist, is considered valid.
The rationale is that, because the stored function might trap exceptions
during execution and still return a valid result, there is no way to decide
when the view is created if a missing table really cause the view to be invalid.
Secondly, testing for existence of tables is now done later during
execution. View security, which consist of trapping errors and return a
generic ER_VIEW_INVALID (to prevent disclosing information) was only
implemented at very specific phases covering *opening* tables, but not
covering the runtime execution. Because of this existing limitation,
errors that were previously trapped and converted into ER_VIEW_INVALID are
not trapped, causing table names to be reported to the user.
This change is exposing an existing problem, which is independent and will
be resolved separately.
mysql-test/r/information_schema_db.result:
Revised the pre-locking code implementation, aligned the tests.
mysql-test/r/sp-error.result:
Revised the pre-locking code implementation, aligned the tests.
mysql-test/r/sp.result:
Revised the pre-locking code implementation, aligned the tests.
mysql-test/r/trigger.result:
Revised the pre-locking code implementation, aligned the tests.
mysql-test/r/view.result:
Revised the pre-locking code implementation, aligned the tests.
mysql-test/t/sp-error.test:
Revised the pre-locking code implementation, aligned the tests.
mysql-test/t/sp.test:
Revised the pre-locking code implementation, aligned the tests.
mysql-test/t/trigger.test:
Revised the pre-locking code implementation, aligned the tests.
sql/lock.cc:
table->placeholder now checks for schema_table
sql/mysqld.cc:
my_message_sql(): invoke internal exception handlers
sql/sp_head.cc:
exec_open_and_lock_tables(): open and lock tables, or return the
continuation destination of this instruction
sql/sp_head.h:
exec_open_and_lock_tables(): open and lock tables, or return the
continuation destination of this instruction
sql/sql_base.cc:
Prelock_error_handler: delay open table errors until execution
sql/sql_class.cc:
THD: add internal error handler, as an exception mechanism.
sql/sql_class.h:
THD: add internal error handler, as an exception mechanism.
sql/sql_update.cc:
table->placeholder now checks for schema_table
sql/table.cc:
st_table_list::hide_view_error(): masked more errors for view security
sql/table.h:
table->placeholder now checks for schema_table, and unopened tables
